Currently, simple steel pipes are screwed together in many drilling facilities. In this manner, a drill string is formed to be several kilometers long and a drill bit is attached at an end of the drill string. In an interior of the pipes, there is a rinsing fluid (e.g., mud) for fulfilling a variety of functions during a drilling process. One of those functions may be an transmission of data via pressure pulses. However, since this data transmission is slow (e.g., a typical transmission rate is around 10 Baud), increasing efforts have been undertaken in drilling industries for obtaining bore information during a drilling operation at higher data transmission rates. For example, a downhole data transmission system of U.S. Pat. No. 6,670,880 is shown to transmit data through a plurality of drilling components of a drill string. Each of the drilling components is connected at its two ends to ends of subsequent drilling components. A coaxial cable within each drilling component extends from one end to the other end of the drilling component and is connected to the coaxial cables of adjacent drilling components. During a drilling operation, a swivel enables communications between the downhole data transmission system and instruments positioned at surface. Other transmission mechanisms are also used. For example, sonar or electric currents across the soil, etc. However, solutions based on a wiring of the drill string (e.g., electrical cables or light guides) have turned out to be most efficient.
Logging of data from the bore during a drilling process has become an essential element in modern crude oil, natural gas or geothermal drillings. This type of data acquisition is also referred to as Measurement While Drilling (MWD) or Logging While Drilling (LWD). Data acquisition is also important for a construction of the bore and a subsequent production of crude oil, gas and/or warm water. A drilling can be operated safely, efficiently and economically only by accurately determining respective relevant measurements. More data from below ground are available, more efficiently and safely can a drilling operation be organized. Therefore, the drilling industry increasingly demands a transmission of data at high data rates (e.g., 200 kBaud) from a depth of several kilometers. This request results in increasing demands on the power of underground measuring units and therefore, an increase in the electric power consumption of the underground measuring units. In order to account for this increasing electric power consumption, the underground measuring units should be supplied with electric energy (e.g., with 200 W) also from the surface.
In PCT Publication No. WO 2010/141969 A2, a device for connecting electrical cables on essential tubular connection elements, which can be screwed to each other, is disclosed, in which a first electrical contact element is firmly arranged on a first connection element and a second electrical contact element is arranged on a second connection element so as to be displaceable in the direction of rotation of the connection element. By means of this device, a problem of the electrical connection between the pipes of the drill string may be solved. The electrical connection has turned out to be reliable, simple and robust for the mechanical connection of pipes (e.g., a rotary movement) and enables a transmission of electric power and/or data under the severe conditions prevailing in the bore, such as a high pollution, the presence of all kinds of liquids, high temperatures and mechanical shocks. Using a drill string constructed in this manner, it is possible to feed electric power into underground measuring units during a drilling process, for example, with the aid of slip ring assemblies arranged at the top-drive and acting as swivels and to read out and evaluate data generated by those underground measuring units.
However, in particular for increasing the safety of the bore, it is also necessary to provide energy supply for underground measuring units and to read out data when no drilling operation is performed and the drill string is dismantled (trip-out) or installed by pipes being assembled (trip-in). In addition, it is of utmost importance to know whether changes relevant to safety occur in the bore, such as, e.g., pressure changes, friction, formation of gas bubbles etc.
In European Patent No. EP 2,273,058 A2, instruments for providing communications with a wired drill pipe during a tripping operation are disclosed. The instruments can be connected to the drill string and comprise so-called sub-coupler heads. A first type of sub-coupler head has a threadless surface which, during the installation in a wired drill pipe, exerts a retaining force against a thread section of the drill pipe via a friction or press fit. The friction or press fit is achieved by spreading the sub-coupler head. A communication element is embedded in the sub-coupler head to couple communicatively to a pipe communication element, if the sub-coupler head is positioned within the receiver end of the wired drill pipe. Inductive couplers and direct connection couplers, among other things, are mentioned as communication elements. A wiring connection, mud-pulse telemetry, electronic telemetry and/or acoustic telemetry are cited as examples of communicative coupling. The material of the sub-coupler head is elastic or deformable, respectively, and soft with regard to the material of the drill pipe so that the thread of the drill pipe is not damaged. In an alternative exemplary embodiment of the sub-coupler head, its surface exhibits a partial thread. The communication device serves only for the transmission of signals, but not for supplying underground measuring units with electric energy.
In U.S. Pat. No. 7,198,118, a communication adapter for a detachable connection to a drilling component outside of the active drilling operation is disclosed. The communication adapter comprises a data transmission coupler for data communication with a transmission system integrated in the drilling component, a mechanical coupler for removably attaching the adapter to the drilling component and an integral data interface comprising a screen, a gauge, a loudspeaker or a light. The mechanical coupler comprises a thread or solenoids or locking mechanisms such as, e.g., elastic clips or clamps. In one exemplary embodiment, the mechanical coupler comprises cams which can be swiveled about a swivel axis into an engagement with an internal thread of the drilling component. The communication adapter serves only for the transmission of signals, but not for supplying underground measuring units with electric energy.
The intention of feeding energy, data and/or control signals into and, respectively, out of the drill string during the trip-in and, respectively, trip-out operation of the bore encounters primarily the following difficulties:                The drill string is not regularly screwed to the slip ring assembly, which, therefore, cannot be used for electrical power supply and communications.        For safety reasons, electric energy supply units, data processing devices and controls are located outside of the drilling rig in a switch cabinet and they must be connected to the drill string via energy supply, status and control lines.        The energy supply, status and control lines must be linked to the drill string via an electromechanical unit which functions highly reliably under the severe operating conditions and in accordance with safety regulations such as those for explosion protection zone 1 and yet is easy to handle for the operating staff, whereby semiautomatic or manual connecting and separating should be possible.        
The disclosed technology is based on the object of providing a solution to the above-discussed problems associated with feeding electric energy, data and/or control signals into and, respectively, out of the drill string during the trip-in and, respectively, trip-out operation of the bore.